code: def to_set(edge_index):
      return set([(i, j) for i, j in edge_index.t().tolist()])
  
file_path: pytorch_cluster/test/test_knn.py
imports: from itertools import product
  import pytest
  import scipy.spatial
  import torch
  from torch_cluster import knn, knn_graph
  from torch_cluster.testing import devices, grad_dtypes, tensor
label_desc: Use image node_id 1 for calling a global function with example usage: to_set(edge_index) and returns: set